Myocardial performance index as predictor of adverse outcomes following mitral valve surgery

AIMS

We aim to determine whether the myocardial performance index, will be a good predictor of adverse outcomes following mitral valve surgery.

METHOD

We prospectively measured pre-operative myocardial performance index in 22 consecutive patients, with moderate to severe mitral insufficiency, undergoing corrective mitral valve surgery. The primary endpoint was predefined as either peri-operative death or congestive heart failure.

RESULTS

The primary endpoint occurred in nine patients. Five of the six patients with myocardial performance index >or=0.7 had primary endpoints. Chi-square testing demonstrated that the primary endpoint was significantly associated with advanced age (>or=70 years) and myocardial performance index >or=0.7 (P=0.003 and 0.01 respectively). There was a trend towards significant association of depressed left ventricle ejection fraction (left ventricle ejection fraction <or=40%) and the primary endpoint (P=0.09). Although left ventricle ejection fraction <or=40% was more sensitive in predicting the primary endpoint, it has lower specificity, accuracy and predictive values than myocardial performance index >or=0.7.

CONCLUSION

Our results suggest that myocardial performance index is a potentially useful predictor of increased risk of peri-operative death or congestive heart failure, in patients with moderate-severe mitral insufficiency undergoing corrective mitral valve surgery. In conjunction with left ventricle ejection fraction, it may be helpful in the pre-operative prognostication of these patients.

Assessment of right ventricular function postretrograde cardioplegia by transesophageal echocardiography

The impact of continuous retrograde cardioplegia (RCP) on right ventricular (RV) function was evaluated prospectively with intraoperative transesophageal echocardiography (TEE) in 36 patients (23 males, 13 females) with a mean age of 60.4 years (ages 24-82). Operative procedures included 12 aortic valve replacements, 16 mitral valve repair/replacements, both with or without an associated cardiac operation, and 8 Ross procedures. Mean cardiopulmonary bypass (CPB) time was 123.3 minutes (66-280 minutes) with an average cross-clamp time of 88.9 minutes (43-199 minutes). The amount of cold blood RCP ranged from 3160-18,500 mL (mean = 7382.5), and the average pulmonary artery pressure was 35/18 mmHg. The coronary sinus was distally snared in 11 patients. TEE documented biventricular global dysfunction in two patients and post-CPB with preservation of the left ventricular function in all other patients. Localized akinesis of the RV apex and outflow tract were noted in three patients, and isolated worsening tricuspid insufficiency of moderate to severe intensity in six patients. Two of the six patients with worsening tricuspid insufficiency belonged to the snared coronary sinus group (11 patients). All of the documented RV dysfunctions were new and showed no correlation with the perfusion data.

IN CONCLUSION

(1) RV apex, RV outflow tract and tricuspid valve were particularly subject to important dysfunction post-RCP; (2) RCP did not protect RV adequately in 11 patients (31%); and (3) TEE is a convenient intraoperative technique in evaluating RV dysfunction.